Various vacuum-producing tools and apparatus powered by an electric motor and designed for picking up debris, dust and liquids are well-known and in common use. One class of such devices is the wet-dry shop vacuum which includes an electric motor which turns a fan disposed within a blower cage in order to create a partial vacuum within a tank to provide suction. Such shop vacuums often have a filter disposed in the tank in front of the blower cage to prevent the blower cage from becoming clogged and to prevent matter which is picked up by the device from being exhausted out of the discharge outlet of the device. There are several disadvantages associated with such shop vacuums and other vacuum units or systems powered by electric motors, which become especially apparent in certain heavy-duty or severe use applications. Examples of such disadvantages include the electric cord for the vacuum unit becoming frayed or broken, and the filter becoming clogged with debris or dust which has been vacuumed up. Moreover, fine powdery substances thus cannot be picked up in any quantity without clogging the filter. The capacity and speed with which shop vacuums pick up liquids is also limited. After liquids are picked up, the typical filter must be allowed to dry before dirt and dust can be picked up or else the filter will quickly become clogged. Also, the ability to pick up combustible materials is limited if the electric motor used in the shop vacuum is sufficiently open to allow sparks generated by the operation of the motor to possibly ignite the materials or airborne particulate or vapors associated therewith. In addition, shop vacuums often create very loud noises during operation, which can be quite bothersome for a number of reasons. Further, the electric motor after some limited period of time will burn out or wear out, thus requiring repair or replacement. This process is often accelerated when contaminants (that is the collected airborne debris, dust or liquids) make their way into the motor housing. This is particularly costly for when the motor is a large electric motor powering a large central vacuum system utilizing duct work or the like to interconnect multiple vacuum stations used by a several workers.
As an alternative, a number of air-powered vacuum-producing apparatus are known which do not suffer from most of the foregoing disadvantages. For example, air-operated vacuuming tools or devices have been utilized for such tasks as removing water and other debris from weather-exposed truck tires which are to be recapped. Typically, the liquids and debris so picked up are collected in a pail or other container. Such devices have the advantage of not requiring any electricity to operate. However, they require a tremendous amount of pressurized air to operate relative to the amount of liquid or debris which they pick up. This makes them objectionably noisy and quite inefficient from an energy standpoint. Also, the capacity (i.e., volume of air sucked up per unit time) and suction power (i.e., the degree of vacuum) of such prior art devices are limited, thus rendering such air-powered vacuuming devices insufficient for a number of applications, particularly where the objects or matter to be picked up are relatively large or heavy.
The object of the present invention is to overcome the foregoing disadvantages and limitations associated with conventional vacuum units and systems powered by electric motors and with conventional air-powered vacuum-producing tools and devices.